Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 170538
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1138 PM MDT Thu Mar 16 2017

.SHORT TERM...(Tonight through Friday night)
Issued at 200 PM MDT Thu Mar 16 2017

Current satellite indicates very little cloud cover across the
west coast, with the next significant weather maker for the
Pacific Northwest spinning northeast of Hawaii beginning to stream
some high clouds into Oregon and NoCal and even those across
northern Utah today. The high level clouds over Utah now still on
track to stream into Colorado this evening allowing for low temps
tonight across northern UT and CO to moderate a few degrees as
compared to last night. Most of this upper level moisture will
have moved east of the region by Friday evening. Temperatures on
Friday will increase once again as a high pressure axis moves over
the region again. The fortunate part with these high daytime
temperatures is that at night the low temperatures are cooling
enough to slow snowmelt into our streams and rivers. Please see
the hydrology section below for awareness of rising rivers and
streams with snowmelt.

.LONG TERM...(Saturday through Thursday)
Issued at 200 PM MDT Thu Mar 16 2017

Saturday is still looking like the hottest and driest day of the
week, with high temperatures once again challenging long standing
records in many places. H5 ensemble mean anomalies are near 200
percent of normal on Saturday, which translate to an unseasonably
warm day. Southwest winds will increase on Saturday afternoon with
the next longwave trough moving onshore the west coast. This
passing trough to our north will flatten the ridge over the region
and cool temperatures back down for Sunday and Monday...but
expecting this will be barely noticed as the pleasant weather
persists. High pressure once again build over the Intermountain
West on Tuesday before a much larger amplitude trough moves
onshore the west coast late Tuesday and quickly progresses toward
the Rockies. Moisture with this system midweek is much more
significant than anything in the last couple of weeks, with
Pacific moisture bringing specific humidity around or above 4g/kg
by Wednesday afternoon. This looks to be a good setup for moisture
in the Abajos, LA Sals, San Juans, and Four Corners valleys
initially on Wednesday/Wednesday night with a shift to favor
moisture in westerly/northwesterly flow on Thursday behind the
associated cold front. The GFS is keeping this weather system as a
closed low while the EC continues to trend weaker with an open
trough. In either case, we are expecting snow level to begin very
high in the mountains on Wednesday in warm southwest flow but then
transition as the cold front passes Wednesday night. H7 temps are
progged at this time to keep snow accumulations out of the
valleys, but dynamics with the trough/closed low may drive snow
lower than the H7 temps would suggest. We will have to keep an eye
on this as the GFS solution with a closed low involved will very
likely change its course and timing before next week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1138 PM MDT Thu Mar 16 2017

Some scattered to broken high level clouds will continue to pass
over the region through 12Z Friday morning before becoming mostly
sunny by Friday afternoon as high pressure amplifies across the
region. Temperatures will warm to well above seasonal levels once
again, which will result in decent mixing. Occasional breezes will
occur during the afternoon but winds should be less than the
previous few days due to the ridge moving overhead. Winds will
follow typical diurnal patterns. VFR conditions will prevail
through the next 24 hours.

&&

.FIRE WEATHER...
Issued at 200 PM MDT Thu Mar 16 2017

Increasing surface winds combined with near record high
temperatures and low humidity values may result in heightened
fire weather this weekend. The potential will be greatest on
Sunday at and below 8000 feet.

&&

.HYDROLOGY...
Issued at 200 PM MDT Thu Mar 16 2017

Very warm temperatures are expected across much of eastern Utah
and western Colorado through this weekend. This will accelerate
snowmelt resulting in increased flows on area waterways and slow
but steady rises in river levels. Temperatures are expected to
cool early next week, which will help to slow the snowmelt.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

$$

SHORT TERM...JAM
LONG TERM...JAM
AVIATION...MDA
FIRE WEATHER...TGJT
HYDROLOGY...TGJT



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